This invention relates to electronic slope detectors and in particular to a device which determines if a time varying electrical signal has a slope which equals or exceeds a predetermined value in a predetermined time.
The slope detector has wide application in a variety of fields where it is desirable to determine if the slope of an electrical signal is equal to or greater than a predetermined magnitude for a predetermined time. The signal itself is the product of the measurement or sensing of a physical phenomenon and the slope of the signal contains useful information which can be extracted for further processing.
The slope detector has particular application in the medical arts where it is sometimes necessary to determine the clotting time of plasma. Others have discovered that as a sample of plasma clots its ability to transmit light decreases. By sensing the rate of change of light transmission and by ascertaining the time at which this rate of change equals or exceeds a predetermined value for a predetermined time, the clotting time of the plasma can be reliably determined.
There is a variety of known slope detectors, however many of them employ a differentiating capacitor, the use of which introduces unwanted errors.
Accordingly, it is an object of this invention to provide a device which determines if the slope of a time varying electrical signal equals or exceeds a predetermined value in a predetermined time. It is a further object of this invention to provide a device which derives relevant information about the slope of a time varying electrical signal without the use of a differentiating capacitor. These and other objects are achieved as follows.